Tom Lewis still hopes to win the award for the best amateur performance at the Open. Photograph: Adrian Dennis/AFP/Getty Images

It would seem almost unedifying if Tom Lewis, whose first 18 holes of the Open Championship offered fairytale material, spends Sunday scrapping for a less salubrious prize than the Claret Jug.

Peter Uihlein's 75 on Saturday – an admirable score, given he played in easily the most severe of the day's conditions – left him seven over for the tournament. That was eight shots worse off than Lewis before the Englishman strode on to the tee for his latest round in the company of a luminary, this time Phil Mickelson.

Lewis's main task from the moment he dropped four shots in his opening eight third-round holes was straightforward. Rather than reignite a challenge for the championship, the 20-year-old has to ensure he does not concede the silver medal awarded for the best amateur performance at the season's third major to Uihlein. A seemingly straightforward task for Lewis now requires a bit of Sunday work.

There is a worst-case scenario and precedent that Lewis must guard against. In 1995, Gordon Sherry's impressive finish at the Scottish Open and stunning start to the Open a week later made him the hottest amateur property in golf. What has been lost in the subsequent years is that Sherry did not even claim the silver medal at St Andrews, Steve Webster did. The Scot's subsequent disappearance from the golfing spectrum, moreover, serves as a warning to the likes of Lewis.

The story of Sherry, though, contrasts to the success enjoyed by Rory McIlroy since he claimed the top amateur prize at the Carnoustie Open of 2007. Despite a slow start to his professional career, Justin Rose has also built on landing abruptly into the spotlight on account of a showing as an amateur at the Open.

All available evidence suggests Lewis will emerge strongly, and not remotely damaged, from his Sandwich visit. Key to that is the strength and ability of those around him, let alone his own prodigious talent. But it would be appropriate for the kid whose name was on everybody's lips on Thursday evening to leave Royal St George's with a tangible reward.

In order to do that, Lewis must press home an advantage over the United States amateur champion which now sits at two strokes. A third-round 76 from Lewis narrowed a gap which few people had even paid attention to onSaturday morning.

An ugly, pulled tee shot on the 3rd triggered the first of three successive bogeys for Lewis. Chances to retrieve that situation in part, on the 6th and 7th, resulted in birdie putts being left short of the hole. As Lewis completed his outward nine in 40 shots, Uihlein was given hope.

Mickelson had played that opening half three shots better than his playing partner. It remains a notable aspect of the American's game that he struggles to such an extent on links courses, not least because he seems to relish it so much.

At an aggregate of level par, Mickelson will retain hope of ending a barren Open run on Sunday. Unlike so many of those who precede him on the leaderboard, he knows what it takes to win a major title. Mickelson is in contention here, of that there is no doubt.

Lewis should not have been perplexed by the wild conditions that the early part of his round was played in. Top amateur players on these shores regularly compete in the most inclement of weather; Lewis's caddie, Lorne Duncan, donned a pair of sandals in a display of how relaxed he was about the wind and rain.

The weight of expectation can be heavier than anything that falls from the sky. Even for someone so relaxed, the reality of sharp focus and scrutiny as he edged towards an outstanding round of 65 on Thursday would naturally prove difficult for Lewis to handle.

Yet the man from Welwyn Garden City steadied himself at the onset of the back nine, carding five straight pars. Mickelson bogeyed the 10th but holed a long putt on 11 to remain within touching distance of the leading pack. As the American moved back to level par with four holes to play, Mickelson's policy of treating this Open as if it were his debut appeared more than a mental gimmick.

Lewis stumbled to another bogey on the 15th, a confident putt on the penultimate hole allowed him a first birdie of the day, but another shot was dropped on 18. Most neutrals hope a two-shot advantage is sufficient to prevent an anticlimax.

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